Please keep in mind that the following data are from a test unit reviewed by Golden Ears - the test unit is not necessarily a representative sample of the model being reviewed.

1. WAV Test Result (Lossless File)

1.1 16bit-44.1kHz Test Signal

16bit, 44.1kHz / Astell&Kern AK120

Frequency response (from 40 Hz to 15 kHz), dB

+0.01, -0.08

Excellent

Noise level, dB (A)

-97.3

Excellent

Dynamic range, dB (A)

96.9

Excellent

THD, %

0.0006

Excellent

THD + Noise, dB (A)

-90.7

Very good

IMD + Noise, %

0.0042

Excellent

Stereo crosstalk, dB

-97.0

Excellent

IMD at 10 kHz, %

0.0041

Excellent

1.2 24bit-192kHz Test Signal

24bit, 192kHz / Astell&Kern AK120

Frequency response (from 40 Hz to 15 kHz), dB

+0.00, -0.03

Excellent

Noise level, dB (A)

-114.2

Excellent

Dynamic range, dB (A)

114.4

Excellent

THD, %

0.0005

Excellent

THD + Noise, dB (A)

-101.7

Excellent

IMD + Noise, %

0.0032

Excellent

Stereo crosstalk, dB

-110.5

Excellent

IMD at 10 kHz, %

0.0008

Excellent

2. Lossy File Test Result

Sampling Frequency : 44.1kHz / Astell&Kern AK120

Test

AK120 Wav

AK120 WMA VBRQ98

AK120 OGG VBRQ10

AK120 MP3 CBR320

Frequency response (from 40 Hz to 15 kHz), dB:

+0.01, -0.10

+0.21, -0.41

+0.10, -0.24

+0.05, -0.35

Noise level, dB (A):

-114.0

-112.6

-106.9

-98.9

Dynamic range, dB (A):

114.0

80.2

94.8

101.2

THD, %:

0.0006

0.0015

0.0011

0.0010

IMD + Noise, %:

0.0018

5.377

0.319

0.011

Stereo crosstalk, dB:

-113.1

-107.6

-107.1

-98.0

3. Optical Input Test Result (24bit-96kHz Test Signal)

Sampling Frequency: 96kHz / Optical In

Frequency response (from 40 Hz to 15 kHz), dB

+0.00, -0.01

Excellent

Noise level, dB (A)

-113.7

Excellent

Dynamic range, dB (A)

113.6

Excellent

THD, %

0.0005

Excellent

THD + Noise, dB (A)

-89.8

Good

IMD + Noise, %

0.0060

Excellent

Stereo crosstalk, dB

-109.0

Excellent

IMD at 10 kHz, %

0.0055

Excellent

A given headphone output may accommodate many different headphones - in general, a smaller load impedance (on headphones) will lead to a larger sound, but at cost of accuracy in measurable data due to the increased current - this cost usually manifests in an increasingly weak bass and elevated crosstalk values as the load impedance decreases. The purpose of the tests to follow is to see how these values change as a function of impedance.

R16:16Ω / R33:33Ω / R62:62Ω / R250:250Ω

Sampling Frequency : 44.1kHz / Astell&Kern - AK120

Test

AK120 R250

AK120 R62

AK120 R33

AK120 R16

Frequency response (from 40 Hz to 15 kHz), dB:

+0.01, -0.10

+0.01, -0.10

+0.01, -0.10

+0.01, -0.10

Noise level, dB (A):

-111.2

-111.1

-111.0

-110.8

Dynamic range, dB (A):

111.1

110.9

110.9

110.8

THD, %:

0.0023

0.0073

0.013

0.021

IMD + Noise, %:

0.0025

0.0071

0.012

0.020

Stereo crosstalk, dB:

-96.8

-97.2

-79.4

-66.4

R16:16Ω / R33:33Ω / R62:62Ω / R250:250Ω

Test Mode : 24bit, 44.1kHz

A lower impedance is desirable on the headphone outputs of amplifiers. The output impedance is closely related to the damping factor, and is one of the most important parameters that determine headphones' performance - desktop amps tend to exhibit high impedance values, corresponding to poor performance.